Handle improper lists in RedactorEncoder

[martosaur]

Hi 👋

Currently, RedactorEncoder can't handle an improper list and would crash a formatter:

iex(1)> LoggerJSON.Formatter.RedactorEncoder.encode([1 | 2], [])
** (FunctionClauseError) no function clause matching in Enum."-map/2-lists^map/1-1-"/2

    The following arguments were given to Enum."-map/2-lists^map/1-1-"/2:

        # 1
        #Function<3.49609762/1 in LoggerJSON.Formatter.RedactorEncoder.encode/2>

        # 2
        2

    (elixir 1.18.2) lib/enum.ex:1714: Enum."-map/2-lists^map/1-1-"/2
    (elixir 1.18.2) lib/enum.ex:1714: Enum."-map/2-lists^map/1-1-"/2
    iex:1: (file)

This PR attempts to fix it. There are probably multiple ways this can be addressed, but I went with inspecting the list after all individual elements were encoded. This way it'll be visible that something isn't right and no data will go unredacted.

Oh, and my personal real world example where the redactor was crashing is when I tried to log Plug.Conn.resp_body, which is of iodata type and is often an improper list.

Let me know what you think!

[kpan2025]

I'm also got this issue, hope to fix it soon, thanks.